David Whythe - BBC Research Career

BBC Research Department, team photo, 1970
BBC Research Department, group photograph, 1970
Dad is second from right, seated in the front row.


His main task (in general terms) was to assess radio signal strength and to predict reception quality at various points around the country.
I remember one of the responsibilities he most enjoyed was to predict the signal strength in the Scottish region, where the mountains tended to mask VHF signals, and where most of the local population lived and worked in the valleys, where signal strength was weakest. He therefore tried to identify the geographical locations for radio transmitter aerials which would give the best reception for the greatest number of people, while also limiting the visual impact of transmitter aerials on the skyline.
Rob climbing on the BBC mobile transmitter aerial, 1961
To test his predictions, he arranged for a temporary test aerial to be mounted at a specified location, and for it to transmit a test signal for a period. He then spent two weeks driving around the Scottish Highlands, testing the signal strength as he went. Those two weeks were heaven for him.

The picture at left is of me in 1961, using his mobile transmitter aerial (collapsed for transport) as a climbing frame!

The Whythe-Fuller slide rule, prototype at top, commercial version belowAs part of Dad's calculations for his predictions, he often needed to use complex numbers - which combine a normal "real" number with an "imaginary" component. Since these were the days before electronic calculators, he used a slide rule as his main tool. But these only supported normal "real" numbers, and could not carry out multiplication or division for complex numbers. So in 1960 he invented what became the Whythe-Fuller slide rule to do this for him.

Front cover of Slide Rule Gazette issue 21, with main feature about David WhytheHe designed the original prototype version (above, in the picture at left), which was built in the BBC workshops, to prove the concept. The design was then passed to the Stanley tool company, who built the commercial version for general sale (below). This brought him a small amount of money by way of the patent rights, but since it had a very limited market (with few people needing to multiply complex numbers) and the period it was on sale was short (production closed in 1967), this was not a major income stream for him. But the relative rarity caused by the limited market and the short production period means that these slide rules are now rare collector's items. As such, Dad was featured as the main subject of the Slide Rule Gazette, issue 21, in Autumn 2021 (the newsletter for the UK Slide Rule Circle).
Presentation of the prototype slide rule at Dad's retirement
At Dad's retirement in 1980, Dr Charles Sandbank, Head of BBC R&D, presented him with his prototype slide rule, to keep as a memento. Or at least, he presented it to Mum, suggesting she use it as a rolling pin, and that she might find it useful for keeping Dad in order.

Dad gritting his teeth, 400 feet up the radio mast at Crystal PalaceDad sent a picture home, of himself scared stiff up a radio mast in 1956
Part of Dad's induction into radio transmission equipment was, early on, to climb a few of the transmitter masts to check out the equipment mounted at the very top.

At left he is pictured in 1960, 400 feet up the transmitter mast at Crystal Palace, while on the right is a photo he sent home in 1956, showing him "scared stiff" up an aerial tower.

Dad in London, year unknown, travelling to Broadcasting House
His work often took him into London, usually to Broadcasting House. On one occasion he was pictured as a typical London commuter.

As you can see, his pipe was a regular part of his "uniform", throughout his life, and his favourite tobacco was Bondman.